Although a plurality of polishing machines having fine grinding or polishing tools, or both, for polishing the most differing workpieces are known, the machined surfaces of structures produced in machining centers and program-controlled milling machines have typically been high-gloss polished by hand to date. When the structures have large volumes for presses, the polishing work to be carried out manually is extremely time-consuming. Furthermore, since the structures often have complex surfaces including roundings, edges, and curvatures, automated polishing of the entire surfaces, including their critical areas, was formerly not possible by means of the program-controlled milling machine. The polishing of pressed and cast parts which, to obtain high gloss, is usually to be carried out in several steps by hand of also by means of power tools, is extremely time-consuming and calls for highly qualified, experienced staff.
In order to polish simply curved glass surfaces in the production of optical lenses, it is known from German patent DE 101 14 625 B3 to remove material in well-calculated fashion on the workpiece surface by fine grinding or polishing using a rotationally driven polishing tool. The polishing tool contains a tool shank which is fixed in a spindle of a special polishing machine or a robot by means of a tool holder. A hollow-cylindrical head is mounted on the tool shank, and a cylindrical polishing member is received in a longitudinally movable fashion in the outwardly open chamber of the head. A polishing suspension impinges on the inner rear side of the polishing member which is moved in rotating and oscillating fashion and forces the polishing member with its annular and cylindrical polishing surface against the curved surface of the glass workpiece. The polishing suspension passes through an annular gap between the polishing element and the chamber wall and reaches the glass surface to be polished. This apparatus cannot be used in program-controlled milling machines and machining centers and cannot process the curvatures which are often narrow in the case of pressed parts with the required accuracy.
In addition, a method and an apparatus for the production of structures is known from German patent application DE 10 2006 017 664 A1, wherein a three-dimensional structure is milled out of a material block by means of a processing machine and then the structure surface is smoothed in several processing operations by fine grinding and polishing using the work spindle movable in five axes. The tools used for polishing have an approximately spherical head which is attached to the free end of a longitudinally movable pin. The polishing head consists of a suitable material deformable within limits, made, for example, of felt, fabric fibers, plastic material, among others. The polishing head is pressed on the structure surface of the respective workpiece, which is to be smoothed, at a predetermined contact pressure by means of an installed spring element, wherein the quantity of the contact pressure can be adjusted via the machine control. However, these polishing operations often create problems with respect to effective supply of the polishing agent to the surface area to be processed.